Can anyone advise me on what sink tips are best to use to run my pike flies a little deeper from my floating line, I'd buy an intermediate line but only have the 1 spool for my Colton reel

Hi have a look on here a BFR 95 for £11 posted and a sink tip for £12 posted Footwear, COUNTRY CLOTHING items in qualityefishing store on eBay!

I think I might mean sinking leaders would the airflo salmon/steelhead polycoated ones do the job?

Yes the airflo polyleaders will do the trick, or Vision also do them. There is also the option of a sink-tip line.

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If you're a defender and he heads it that low you take his head off, it's as simple as that. - Roy Keane

Snowbee also do 10ft poly leaders that work well with a short armacore leader from that mate. About £6 each if i remember rightly.